Devices and methods for assisting valve function, replacing venous valves, and predicting valve treatment success

ABSTRACT

Devices and methods for assisting valve function, replacing venous valves, and predicting valve treatment successes. In at least one embodiment of an endograft valve device of the present disclosure, the device comprises an endograft body configured for expansion from a collapsed configuration to an expanded configuration within a luminal organ and comprising a first portion having a proximal end defining a proximal end aperture and a distal end defining a distal end aperture, the first portion tapering toward the distal end so that the distal end aperture has a relatively smaller cross-sectional area than the proximal end aperture when the valve device is expanded, and a valve portion positioned at or near the distal end of the first portion, the valve portion configured to receive fluid flowing through the distal end aperture of the first portion.

PRIORITY

The present application is related to, claims the priority benefit of,and is a U.S. continuation patent application of, U.S. patentapplication Ser. No. 13/539,607, filed Jul. 2, 2012 and issued as U.S.Pat. No. 10,238,483 on Mar. 26, 2019, which is related to, and claimsthe priority benefit of, U.S. Provisional Patent Application Ser. No.61/547,378, filed Oct. 14, 2011, and U.S. Provisional Patent ApplicationSer. No. 61/535,689, filed Sep. 16, 2011. The contents of each of theseapplications are incorporated by reference in their entirety into thisdisclosure.

BACKGROUND

It has been known for several years that the three contributing factorsto venous thrombosis are stasis (slow blood flow), changes in bloodcomposition, and changes in vessel wall. These three contributingfactors are known as Virchow's triad.

Venous insufficiency is a complex disease that involves thrombosis(blood clot abnormalities and/or endothelial dysfunction), venoushypertension, reverse flow (reflux), and venous remodeling, amongstothers. The two major contributors to venous insufficiency are venousocclusion and valve incompetence (reflux).

Blood stasis promotes a thrombogenic response through variousbiochemical activators. Attempts have been made to create percutaneousvenous valve stent systems to replace a prolapsed or otherwisedysfunctional venous valve, but no attempt has previously been provensuccessful. In order for such a system to work, one of the contributingfactors to venous blood thrombosis, namely stasis, must be overcome inorder for the valve to remain patent and to avoid thrombosis/clotting

A valve device or system, operable to replace a prolapsed or otherwisedysfunctional venous valve that effectively operates and overcomes thestasis contributing factor, would be well-received in the marketplace.In addition, a device useful to assist blood flow through a bloodvessel, methods of using the same, and methods for predicting apotential success for an individual patient in connection with apotential valve treatment procedure, would also be well-received in themarketplace.

BRIEF SUMMARY

In at least one exemplary embodiment of an endograft valve device of thepresent disclosure, the endograft valve device comprises an endograftbody configured for expansion from a collapsed configuration to anexpanded configuration within a luminal organ, the endograft bodycomprising a first portion having a proximal end defining a proximal endaperture and a distal end defining a distal end aperture, the firstportion tapering toward the distal end so that the distal end aperturehas a relatively smaller cross-sectional area than the proximal endaperture when the valve device is expanded, and a valve portionpositioned at or near the distal end of the first portion, the valveportion configured to receive fluid flowing through the distal endaperture of the first portion. In another embodiment, the endograftvalve device further comprises a second portion having a second portionproximal end defining a second portion proximal end aperture and asecond portion distal end defining a second portion distal end aperture,the second portion tapering toward the second portion distal end so thatthe second portion distal end aperture has a relatively smallercross-sectional area than the second portion proximal end aperture whenthe valve device is expanded, wherein the distal end of the firstportion is adjacent to the second portion proximal end, and wherein thevalve portion is positioned at or near the second portion proximal end.

In at least one exemplary embodiment of an endograft valve device of thepresent disclosure, the endograft valve device comprises an endograftbody configured for expansion within a luminal organ, the endograft bodycomprising a first portion having a proximal end defining a proximal endaperture and a distal end defining a distal end aperture, the firstportion tapering toward the distal end so that the distal end aperturehas a relatively smaller cross-sectional area than the proximal endaperture when the valve device is expanded, a second portion having aproximal end defining a proximal end aperture and a distal end defininga distal end aperture, the second portion tapering toward the distal endso that the distal end aperture has a relatively smaller cross-sectionalarea than the proximal end aperture when the valve device is expanded,wherein the distal end of the first portion is adjacent to the proximalend of the second portion, and a valve portion positioned at or near theproximal end of the second portion, the valve portion configured toreceive fluid flowing through the distal end aperture of the firstportion. In another embodiment, the endograft body is configured toexpand from a collapsed configuration to an expanded configuration. Inyet another embodiment, the endograft body has a first configuration,the first configuration sized so that the endograft body may fit withinthe luminal organ. In an additional embodiment, the endograft has asecond configuration, the second configuration sized so that theendograft body may be securely positioned within the luminal organ uponexpansion.

In at least one exemplary embodiment of an endograft valve device of thepresent disclosure, the valve portion is coupled to the first portion.In an additional embodiment, the valve portion is coupled to the secondportion. In yet an additional embodiment, the endograft body is sizedand shaped to fit around a guidewire. In another embodiment, theendograft body is sized and shaped to fit around a catheter. In yetanother embodiment, the endograft body is capable of expanding due toinflation of a balloon coupled to the catheter.

In at least one exemplary embodiment of an endograft valve device of thepresent disclosure, when the endograft body is expanded within theluminal organ, an outer portion of the endograft body contacts theluminal organ, an inner portion of the endograft body is configured topermit fluid to flow therethrough. In another embodiment, the outerportion defines an outer portion wall, and the inner portion defines aninner portion wall. In yet another embodiment, the outer portion definesan outer portion relative surface, and the inner portion defines aninner portion relative surface. In at least one exemplary embodiment ofan endograft valve device of the present disclosure, when the endograftbody is expanded within the luminal organ, fluid flowing through thefirst portion increases in velocity as the fluid approaches the valveportion. In an additional embodiment, when the endograft body isexpanded within the luminal organ, fluid flowing through the firstportion increases in velocity as the fluid approaches the valve portionand increases shear stresses at the valve portion. In yet an additionalembodiment, the valve portion comprises leaflets.

In at least one exemplary embodiment of an endograft valve device of thepresent disclosure, the endograft valve device further comprises ananti-clotting agent positioned upon at least a portion of the endograftvalve device. In another embodiment, the anti-clotting agent ispositioned upon at least an inner portion of the endograft valve device.In yet another embodiment, the anti-clotting agent is positioned upon atleast an outer portion of the endograft valve device. In an additionalembodiment, the anti-clotting agent is selected from the groupconsisting of heparin, thrombomodulin, and/or endothelial cell proteinC. In yet an additional embodiment, the endograft body is comprises of abiologically-compatible material selected from the group consisting ofpolytetrafluoroethylene, Gore-Tex®, and/or a nickel titanium alloy, suchas nitinol. In an additional embodiment, the endograft valve devicefurther comprises a guidewire and a catheter, wherein the catheter isconfigured to fit around the guidewire, and wherein the endograft valvedevice is configured to fit around the catheter. In yet an additionalembodiment, the endograft valve device comprises a venous endograftvalve device configured to fit within a vein.

In at least one exemplary embodiment of a valve system of the presentdisclosure, the valve system comprises an exemplary endograft valvedevice of the present disclosure, a guidewire, and a catheter, whereinthe catheter is configured to fit around the guidewire, and wherein theendograft valve device is configured to fit around the catheter. Inanother embodiment, the catheter comprises a balloon catheter.

In at least one exemplary embodiment of a method of using an exemplaryendograft valve device of the present disclosure, the method comprisesthe steps of introducing a guidewire into a luminal organ of a patient,advancing an endograft valve device of the present disclosure along theguidewire to a desired location within the luminal organ, and expandingthe endograft valve device within the luminal organ. In anotherembodiment, the method further comprises the step of withdrawing theguidewire from the luminal organ. In yet another embodiment, the luminalorgan is a vein, and the endograft valve device is configured as avenous endograft valve device.

In at least one exemplary embodiment of a method of determining whethera patient is suitable for a valve procedure of the present disclosure,the method comprises the steps of obtaining data indicative to apatient's venous geometry at a first location, obtaining data indicativeof a flow velocity of blood within a vein of the patient at or near thefirst location, preparing a digital model of the vein of the patientusing the data indicative to the patient's venous geometry and/or thedata indicative of the flow velocity to obtain patient venous data, anddetermining whether the patient is suitable for a valve procedure basedat least in part on the patient venous data. In another embodiment, thesteps of obtaining data are performed using duplex ultrasonography. Inyet another embodiment, the steps of obtaining data are performed usingan impedance device selected from the group consisting of an impedancewire and an impedance catheter. In an additional embodiment, the stepsof obtaining data are performed using an impedance device comprising adevice body and at least four electrodes positioned thereon, the atleast four electrodes comprising two electrodes configured to excite anelectric field and two electrodes configured to obtain a conductancemeasurement within the electric field.

In at least one exemplary embodiment of a method of determining whethera patient is suitable for a valve procedure of the present disclosure,the step of preparing the digital model of the vein of the patient isperformed using the data indicative to the patient's venous geometry andthe data indicative of the flow velocity to obtain patient venous data.In an additional embodiment, the step of preparing the digital model ofthe vein of the patient is performed using the data indicative to thepatient's venous geometry to prepare a first digital model and the dataindicative of the flow velocity to prepare a second digital model,wherein the patient venous data is indicative of the first digital modeland the second digital model. In yet an additional embodiment, themethod further comprises the step of incorporating data indicative of atleast one valve into the digital model.

In at least one exemplary embodiment of a method of determining whethera patient is suitable for a valve procedure of the present disclosure,the step of determining whether the patient is suitable for a valveprocedure based at least in part on the patient venous data and the dataindicative of at least one valve. In another embodiment, the step ofdetermining whether the patient is suitable for a valve procedure isbased upon at least patient venous data indicative of flow and shearstress, and an ultimate determination is based upon a comparison of thepatient venous data indicative of flow and shear stress to at least onethreshold.

In at least one exemplary embodiment of a method of preparing a digitalmodel of a vein of the present disclosure, the method comprising thesteps of obtaining data indicative to a patient's venous geometry at afirst location within the patient, obtaining data indicative of a flowvelocity of blood within a vein of the patient at or near the firstlocation, preparing at least one digital model of the vein of thepatient using the data indicative to the patient's venous geometryand/or the data indicative of the flow velocity to obtain patient venousdata, and using the patient venous data for at least one test purpose,the at least one test purpose selected from the group consisting of i)determining whether the patient is suitable for a valve procedure basedat least in part on the patient venous data and ii) testing one or morevirtual valve device configurations in at least one simulation using thedigital model. In another embodiment, the steps of obtaining data areperformed using a device selected from the group consisting of a duplexultrasound device, an impedance wire, and impedance catheter, animpedance device comprising a device body and at least four electrodespositioned thereon, the at least four electrodes comprising twoelectrodes configured to excite an electric field and two electrodesconfigured to obtain a conductance measurement within the electricfield. In an additional embodiment, the step of using the patient venousdata is performed by using the patient venous data for the at least onetest purpose of determining whether the patient is suitable for thevalve procedure based at least in part on the patient venous data. Inyet an additional embodiment, the method further comprises the step ofincorporating data indicative of at least one valve into the digitalmodel. In another embodiment, the determination of whether the patientis suitable for the valve procedure based at least in part oninformation selected from the group consisting of i) the patient venousdata and the data indicative of at least one valve, and ii) patientvenous data indicative of flow and shear stress, and wherein an ultimatedetermination is based upon a comparison of the patient venous dataindicative of flow and shear stress to at least one threshold.

In at least one exemplary embodiment of a method of preparing a digitalmodel of a vein of the present disclosure, the step of using the patientvenous data is performed by using the patient venous data for the atleast one test purpose of testing one or more virtual valve deviceconfigurations in at least one simulation using the digital model. In anadditional embodiment, the method further comprises the step ofadjusting the one or more virtual valve device configurations andretesting the adjusted one or more virtual valve device configurations.In yet an additional embodiment, the method further comprises the stepof preparing a physical valve device based upon at least one of theadjusted one or more virtual valve device configurations.

In at least one exemplary embodiment of an external assist device of thepresent disclosure, the device comprises a cuff configured to fit arounda blood vessel and further configured to periodically compress the bloodvessel, and a processor operably coupled to the cuff, the processorconfigured to control a compression rate and a relaxation rate, whereinwhen the device is positioned around the blood vessel at a firstlocation, operation of the processor causes the cuff to compress theblood vessel and relax compression of the blood vessel, wherebyrelaxation at the relaxation rate causes blood to move through the bloodvessel at the first location. In another embodiment, the compressionrate is slower than the relaxation rate. In yet another embodiment, thedevice further comprises a power source operably coupled to the cuff,the power source configured to provide power to the cuff and/or theprocessor to facilitate compression and relaxation of the cuff. In anadditional embodiment, the device further comprises a connector coupledto the power source and to the cuff, the connector configured to allowpower from the power source to be transmitted therethrough to the cuff.In yet an additional embodiment, the connector comprises a wire.

In at least one exemplary embodiment of an external assist device of thepresent disclosure, the processor is configured so that the compressionrate and the relaxation rate can be changed to a different compressionrate and a different relaxation rate. In an additional embodiment, whenthe device is positioned distal to a blood vessel valve, operation ofthe device causes blood to flow through the vessel valve toward thedevice. In yet an additional embodiment, the blood vessel valve isselected from the group consisting of a native valve and a prostheticvalve. In another embodiment, when the device is positioned around theblood vessel at a first location, the blood flows through the bloodvessel at the first location a first rate without operation of thedevice, and the blood flows through the blood vessel at the firstlocation at a second rate during operation of the device, wherein thesecond rate is faster than the first rate. In yet another embodiment,when the device is positioned around the blood vessel at a firstlocation, the blood flows through the blood vessel at the first locationa first rate range without operation of the device, and the blood flowsthrough the blood vessel at the first location at a second rate rangeduring operation of the device, wherein the second rate range has afaster top rate than the first rate range.

In at least one exemplary embodiment of a method of facilitating bloodflow through a blood vessel of the present disclosure, the methodcomprises the steps of positioning an exemplary external assist deviceof the present disclosure around a blood vessel, and operating theexternal assist device to alternately compress the blood vessel andrelax compression of the blood vessel, wherein relaxation of compressioncauses blood to flow through the blood vessel. In another embodiment,relaxation of compression causes blood to flow through the blood vesselat a faster rate than a native blood flow rate. In yet anotherembodiment, the step of operating the external assist device comprisesoperating the external assist device to alternative compress the bloodvessel at a first rate and to relax compression of the blood vessel at asecond rate, wherein the second rate is faster than the first rate.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed embodiments and other features, advantages, anddisclosures contained herein, and the matter of attaining them, willbecome apparent and the present disclosure will be better understood byreference to the following description of various exemplary embodimentsof the present disclosure taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 shows a portion of a guidewire used to position an exemplaryendograft valve device into a luminal organ, according to at least oneexemplary embodiment of the present disclosure;

FIG. 2 shows an endograft valve device in a first configurationpositioned over a guidewire, according to at least one exemplaryembodiment of the present disclosure;

FIG. 3 shows an endograft valve device in a second configurationpositioned over a guidewire, according to at least one exemplaryembodiment of the present disclosure;

FIG. 4 shows an endograft valve device in a second configuration,according to at least one exemplary embodiment of the presentdisclosure;

FIG. 5 shows fluid velocities (represented by position and length ofarrows) when a valve portion of an endograft valve device is open,according to at least one exemplary embodiment of the presentdisclosure;

FIG. 6 shows fluid velocities (represented by position and length ofarrows) when a valve portion of an endograft valve device is partiallyclosed, according to at least one exemplary embodiment of the presentdisclosure;

FIG. 7 shows a block diagram of components of a valve system, accordingto at least one exemplary embodiment of the present disclosure;

FIG. 8 shows a diagram of method steps, according to at least oneexemplary embodiment of the present disclosure;

FIG. 9 shows steps of a method of determining whether a patient issuitable for a valve procedure, according to at least one exemplaryembodiment of the present disclosure;

FIG. 10A shows an external assist device positioned around a bloodvessel, according to at least one exemplary embodiment of the presentdisclosure;

FIG. 10B shows an external assist device positioned around andconstricting a blood vessel, according to at least one exemplaryembodiment of the present disclosure;

FIG. 11 shows an external assist device positioned around a blood vesseland an endograft valve device positioned within a vessel, according toat least one exemplary embodiment of the present disclosure; and

FIG. 12 shows steps of a method of facilitating blood flow through ablood vessel, according to at least one exemplary embodiment of thepresent disclosure.

An overview of the features, functions and/or configurations of thecomponents depicted in the various figures will now be presented. Itshould be appreciated that not all of the features of the components ofthe figures are necessarily described. Some of these non-discussedfeatures, such as various couplers, etc., as well as discussed featuresare inherent from the figures themselves. Other non-discussed featuresmay be inherent in component geometry and/or configuration.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of this disclosure is thereby intended.

With respect to patient treatment for valve and/or venous insufficiency,the disclosure of the present application includes a strategy based onthe following three pillars, namely (1) that valve insufficiency must betreated, (2) that no particular therapy can apply to the entire patientpopulation given the various stages of venous insufficiency and thecomplex etiology thereof, and (3) that no valve can function long-termin the absence of flow (and more specifically shear stress). The presentdisclosure addresses each pillar.

The first pillar (namely that valve insufficiency must be treated) isaddressed by way of one or more exemplary endograft valve devices.

Shear Enhancing Valve

An exemplary endograft valve device 100 of the present disclosure isdescribed as follows. As shown in FIG. 3, for example, an exemplaryvalve device 100 of the present disclosure comprises an endograft body102 having a first portion 104, a second portion 106, and a valveportion 108. Endograft body 102, in various embodiments, is configuredto fit within a luminal organ and further configured for expansionwithin the luminal organ. The first portion 104 of the endograft body102, as shown in FIG. 3 in an expanded configuration, has a proximal end110 defining a proximal end aperture 112 and a distal end 114 defining adistal end aperture 116, the first portion 104 tapering toward distalend 114 so that distal end aperture 116 has a relatively smallercross-sectional area than proximal end aperture 112. Second portion 106of the endograft body 102, as shown in FIG. 3 in an expandedconfiguration, also has a proximal end 118 defining a proximal endaperture 120 and a distal end 122 defining a distal end aperture 124,the second portion 106 tapering toward distal end 122 so that distal endaperture 124 has a relatively smaller cross-sectional area than proximalend aperture 120. As shown in FIG. 3, and in various embodiments of thepresent disclosure, distal end 114 of first portion 104 is positionedadjacent to (and/or coupled to) proximal end 118 of second portion 106.Valve portion 108, as referenced above and shown in FIGS. 3 and 4 forexample, is positioned at or near proximal end 118 of second portion 106(or coupled to first portion 104 or second portion 106), wherein valveportion 108 is configured to receive fluid flowing through distal endaperture 116 of first portion 104.

An exemplary endograft valve device 100 of the present disclosure may bepositioned within a luminal organ of a patient as follows. In at leastone embodiment, and as shown in FIG. 1, a guidewire 200 having anoptional compliant end 202 may be inserted into a lumen 250 of a luminalorgan 252 of a patient. In at least one embodiment, luminal organ 252comprises a patient's vein, and an exemplary endograft valve device 100of the present disclosure is configured to fit within the patient's veinand configured to operate in accordance with the present disclosure.

Upon insertion and placement of a portion of a guidewire 200 within aluminal organ 252, an exemplary endograft valve device 100 of thepresent disclosure may be advanced over guidewire 200 to a desiredlocation within luminal organ 252 as shown in FIG. 2. As shown in FIG.2, endograft valve device 100 is in a first, or collapsed,configuration, and as shown in FIG. 3, endograft valve device 100 is ina second, or expanded, configuration. Endograft valve device 100 may bepositioned around and/or coupled to an optional catheter 260, as shownin FIG. 2, to facilitate positioning of endograft valve device 100within luminal organ 252. Expansion of endograft valve device 100 may bedue to movement of guidewire 200, movement of optional catheter 260,inflation of a balloon 702 (as shown in FIG. 7, for example) positionedupon catheter 260, or other mechanisms/procedures known to facilitateexpansion of an endograft and/or stent.

A side view of an exemplary endograft valve device 100 is shown in FIG.2, while a cross-sectional side view of an exemplary endograft valvedevice 100 is shown in FIG. 3. Expansion of endograft valve device 100(from FIG. 2 to FIG. 3) causes at least a portion of endograft valvedevice 100 to physically contact luminal organ 252 as shown in FIG. 3.As shown in FIG. 3, an outer portion 300 of endograft valve device 100contacts luminal organ 252, while an inner portion 302 of endograftvalve device 100 is configured so that fluid may flow therethrough andthrough valve portion 108. Outer portion 300 may generally define anouter portion wall 310, and inner portion 302 may generally define aninner portion wall 312, as shown in FIG. 3. In at least one embodiment,outer portion wall 310 and/or inner portion wall 312 may be relativewalls, as endograft body 102 may itself comprise a mesh that does notcreate a formal wall. In such an embodiment, for example, outer portion300 may define an outer portion relative surface 320, and inner portion302 may define an inner portion relative surface 322, as shown in FIG.4. As shown in each of FIGS. 3 and 4, the interior portion of anexemplary endograft valve device 100 is generally referred to as a lumen350, whereby lumen 350 tapers toward distal end 114 of first portion 104and again tapers toward distal end 122 of second portion 106.

FIG. 4 shows an exemplary endograft valve device 100 positioned within alumen 250 of a luminal organ 252 with guidewire 200 and optionalcatheter 260 withdrawn. FIG. 4 shows “CSA1” and “CSA2,” which areindicative of a first cross-sectional area and a second cross-sectionalarea, respectively. As shown in FIG. 4, CSA1 is relatively larger thanCSA2, with CSA1 being indicative of a proximal end aperture 112 of firstportion 104, and with CSA2 being indicative of a distal end aperture 116of first portion 104. As shown therein, first portion 104 tapers inwardtoward valve portion 108.

Valve portion 108, as generally referenced above, is configured in atleast one embodiment as a venous valve system. In at exemplaryembodiment, valve portion 108 is configured as an effective bicuspidvalve system for a vein, noting that the arterial system hassubstantially higher shear stresses than the venous system. In view ofthe same, exemplary valve portions 108 of the present disclosure areconfigured to increase shear stress at the leaflets 500 of valve portion108 as shown in FIG. 5 so that they effectively operate as venousvalves.

As shown in FIGS. 3-6, exemplary endograft valve devices 100 areprovided for potential use within a patient's body instead of atraditional stent that may carry a valve. As generally referenced aboveand shown in FIGS. 3-6, endograft valve devices 100 are configured totaper endoluminally, either linerally as shown in the figures or in someother fashion, so that blood flowing therethrough will increase invelocity and hence increase the shear stress at valve portion 108.

Conservation of mass requires that volumetric flow rate (Q) to remainconstant throughout the graft (i.e., Q=constant=V*CSA, where V and CSArepresent the velocity of blood and luminal cross-sectional area of theendograft). Since the CSA is made, by novel design of the variousendograft valve devices 100 of the present disclosure, to decreasetowards valve portion 108 (i.e., CSA2<CSA1 as shown in FIG. 4), thevelocity will be much larger at valve portion 108. The wall shear stress(WSS, referring to the stresses of inner portion 302 of endograft valvedevice 100) is related to the CSA as WSS˜1/CSA3/2 (Poiseuille's law) andhence any decrease in CSA will amplify the WSS. For example, a 10%decrease in diameter (CSA˜D2) is expected to increase the WSS by 33%.

The increase in WSS and the corresponding reduction in thrombogenecityat the valve is weighted against the potential increase in the pressuredrop (ΔP, as shown in FIG. 5) to overcome the resistance to flow. A 50%decrease in CSA, for example is non-flow limiting (i.e., only a minimalpressure drop). Hence, even at this level of CSA design, the WSS can benearly tripled (˜2.8×). A reverse tapering on the distal portion of thevalve, in at least one embodiment and as shown in FIG. 6, is consideredto ensure flow recirculation and hence the establishment of a negativepressure drop to close valve portion 108.

The present disclosure considers various hemodynamic variables to ensurea correct design that prevents stasis. The third point of the triad,namely changes in the vessel wall as referenced herein, can beconsidered as various endograft valve devices 100 can be coatedsimilarly to a luminal organ (such as a biological vein, for example) atleast acutely until the endograft valve device 100 endothelializes. Suchconsiderations may require that the inner portion 302 (such as innerportion wall 312 or inner portion relative surface 322, for example) ofthe endograft valve device 100 be at least partially covered or coatedone or more anti-clotting agents, such as, for example, heparin,thrombomodulin, endothelial cell protein C, and/or another anti-clottingagent. FIG. 5 shows agent 510 positioned upon endograft valve device100. In addition to providing an anticoagulant endoluminal surface (suchas inner portion wall 312 or inner portion relative surface 322, forexample), the same can also be provided to the endograft outer portion300 (such as outer portion wall 310 or outer portion relative surface320, for example) to dissolve any existing clots in the luminal organupon deployment of the endograft valve device 100.

Various embodiments of endograft valve devices 100 of the presentdisclosure may be made of one or more standard biologically-compatiblematerials, such as polytetrafluoroethylene (PTFE), Gore-Tex®, etc.,containing, for example, a nickel titanium alloy such as nitinol and/oranother memory metal in the endograft body 102 so that the desiredmemory shape of the endograft valve device 100, in an open or a closedconfiguration, is accomplished while maintaining the desired hemodynamiceffects noted above.

At least one exemplary embodiment of a valve system 700 of the presentdisclosure is shown in the block diagram of FIG. 7. As shown in FIG. 7,an exemplary valve system 700 comprises a number of components of anexemplary endograft valve device 100 of the present disclosure, such asendograft body 102, valve portion 108, etc. In addition, an exemplaryvalve system 700 may comprise one or more components useful to deliverand/or position an exemplary valve device 100 of the present disclosure,including a guidewire 200, a catheter 260, and an optional balloon 702coupled to or positioned adjacent to catheter 260.

FIG. 8 shows a diagram of steps of an exemplary method of using anendograft valve device 100 and/or valve system 700 of the presentdisclosure. As shown in FIG. 8, an exemplary method 800 comprises thesteps of introducing a guidewire into a luminal organ (such as a vein)of a patient (an exemplary guidewire insertion step 802) and advancingan endograft valve device 100 along guidewire 200 to a desired locationwithin a patient (an exemplary advancement step 804). Endograft valvedevice 100 is then expanded as referenced herein (an exemplary expansionstep 806), and the guidewire 200 and/or any other device used to deliverendograft valve device 100 (such as a catheter 260, for example), iswithdrawn from the area of the endograft valve device 100 (an exemplaryremoval step 808).

The second pillar, namely that no particular therapy can apply to theentire patient population given the various stages of venousinsufficiency and the complex etiology thereof, is addressed as follows.

Patient-Specific Virtual Venous Valve Simulation

An analogy can be drawn with mitral valve and heart failure (HF) whoseetiology may be of ischemic, electrical, or valvular origin. A number oftherapies for HF exist such as revascularization (such as coronaryartery bypass graft (CABG) surgery and percutaneous coronaryintervention (PCI)), valve replacement, cardiac resynchronizationtherapy (CRT), use of a left ventricular assist device (LVAD), and thelike. Each of these therapies has guidelines for patient selection(inclusion/exclusion criterion). A similar paradigm for patientselection must be established for venous insufficiency in order for atherapy to be effective.

The disclosure of the present application includes a patient-specific,physics-based approach to determine whether or not the patient issuitable for a potential vein valve procedure. Such an approach, in atleast one embodiment, may be useful to develop a validated,patient-specific, physics-based computational model to predict theclinical function of a prosthetic valve replacement device. Existingclinical imaging modality, such as duplex ultrasonography (US) may beused in connection therewith to provide both the venous geometry andflow velocity of a patient.

An exemplary patient selection method of the present disclosure uses oneor more computer models of various venous valves, whereby said valvescan be virtually implanted into a model of the specific patient'sgeometry. Various laws of physics, such as the conservation of mass andmomentum, can be used in conjunction with the patient-specific boundarycondition (flow velocity) to simulate the entire shear field on thevalve leaflets as well as the mechanical stresses and strains in theleaflets and/or other functional surfaces of the devices. Various sampleprototype devices may also be tested in said simulations, providing dataindicative of the temporal and spatial distributions of the stresses.These simulations would then provide the physical predictions of theexpected levels of the mechanical environment of the prototype valvesand their propensities for success or failure based, in part, on thevarious intramural stresses and strains in the valve device materials.

By way of example, patients that have low shear stresses (i.e., stasis)on the valve leaflets can be excluded since these patients are likely tohave a poor outcome. The relation between the cutoff for the variousmechanical forces, deformations, and biological responses can bedetermined through in vivo experiments that include realistic models ofvenous hypertension and insufficiency (e.g., venous hypertension usingan arteriovenous (AV) fistula and occlusion models to perturb flow andshear stress and evaluate the biological response of the valve implant).Hence, various guidelines and criterion for acceptable mechanicalregimes in animal studies and from the published literature can beestablished and used to guide the initial patient experience.

Exemplary computational platforms for both fluid and solid mechanics ofa valve can be obtained using duplex US, an impedance device (asreferenced below), or another mechanism useful to obtain geometric andflow data of a valve within a vessel. Such a computer simulation of aflow field and wall stress can be generated for an idealized valve withidealized geometries and flows, and said platforms can then be repeatedfor specific patients, so that flows and stresses representative of aspecific patient can be provided.

As can be identified by such a platform, idealized valves prominentlyshow regions of stagnant flow in the base region of the valve under theprovided flow conditions, as well as showing flow alterations at thehinge region of leaflets. Flow rates and direction can then be indicatedusing a series of arrows to show direction of flow (via arrow point)within a vessel and rate of flow (as given by the overall length of thearrows). A longer arrow denotes a faster flow rate. Wall stresses can beshown using, for example, various colors or pixel concentrations to showareas with higher stresses (generally at or near the valve leaflets) andareas of lower stresses (generally away from the valve leaflets).

To minimize ad hoc assumptions in the simulations, accurate data wouldbe established based upon the anatomy (geometry) and material propertiesof both the potentially-used prosthetic valve and the vein itself.Furthermore, and in addition to duplex US, additional technologies (suchas impedance wires and catheters, for example) can be leveraged todetermine both the size of the vein to match the prosthesis (to preventmigration) as well as compliance of the vessel (for accurate simulationof vein wall motion and coupling to blood flow).

As such, the various virtual simulations used to test variousdevice/valve designs would allow researchers to design and redesign suchdevices until the devices/valves have the desired functionality.Specific devices/valves, including those specific to venous diseases,can be optimized so that their use in vivo would be effective for anynumber of luminal organ needs.

Accordingly, the present disclosure includes disclosure of a method ofdetermining whether a patient is suitable for a valve procedure. In atleast one embodiment of a method 900, as indicated by the method stepsshown in FIG. 9, method 900 comprises the steps of obtaining dataindicative to a patient's venous geometry at a first location (anexemplary first data obtaining step 902) and obtaining data indicativeof a flow velocity of blood within a vein of the patient at or near thefirst location (an exemplary second data obtaining step 904), whereinsteps 902 and 904 can be performed in either order. Method 900, invarious embodiments, further comprises the steps of preparing a digitalmodel of the vein of the patient using the data indicative to thepatient's venous geometry and/or the data indicative of the flowvelocity to obtain patient venous data (an exemplary digital modelpreparation step 906), and determining whether the patient is suitablefor a valve procedure based at least in part of the patient venous data(an exemplary determination step 908).

In at least one embodiment, steps 902 and/or 904 is/are performed usingduplex ultrasonography. In various embodiments, steps 902 and/or 904is/are performed using an impedance device, such as an impedance wireand an impedance catheter. An exemplary impedance device may comprise adevice body and at least four electrodes positioned thereon, wherein theat least four electrodes comprising two electrodes configured to excitean electric field and two electrodes configured to obtain a conductancemeasurement within the electric field.

In various embodiments of methods 900 of the present disclosure, digitalmodel preparation step 906 is performed using the data indicative to thepatient's venous geometry and the data indicative of the flow velocityto obtain patient venous data. In other embodiments, digital modelpreparation step 906 is performed using the data indicative to thepatient's venous geometry to prepare a first digital model and the dataindicative of the flow velocity to prepare a second digital model,wherein the patient venous data is indicative of the first digital modeland the second digital model.

In at least one embodiment of a method 900 of the present disclosure,and as shown in FIG. 9, method 900 further comprises the step ofincorporating data indicative of at least one valve into the digitalmodel (an exemplary valve data incorporation step 910). Step 910 may beperformed by incorporating native valve data or prosthetic valve datatherein. Upon performance of step 910, in at least one embodiment,determination step 908 can be performed based at least in part oninformation including the patient venous data and the data indicative ofat least one valve and/or patient venous data indicative of flow andshear stress. Further and in at least one embodiment, an ultimatedetermination can be made based upon a comparison of the patient venousdata indicative of flow and shear stress to at least one threshold.

An exemplary method 900, as shown in FIG. 9, may comprise the step oftesting one or more virtual valve device configurations in at least onesimulation using the digital model prepared in digital model preparationstep 906 (an exemplary valve testing step 912). In at least oneembodiment, the device configurations can be incorporated into thedigital model such as by valve data incorporation step 910 referencedabove. Valve testing step 912, as shown in FIG. 9, may be performedafter digital model preparation step 906 and optionally after valve dataincorporation step 910, and involves performing at least one simulationusing the digital model. Determination step 908 and valve testing step912 may be generally referred to herein as a test purpose.

Valve testing step 912, in various embodiments, may be performed todetermine whether or not a virtual valve model is suitable for thepatient that the digital model is based upon. For example, if a virtualvalve model is tested in valve testing step 912 and it does not performoptimally, the virtual valve model can be modified and retested. In viewof the same, an exemplary method 900 of the present disclosure mayfurther comprise the steps of adjusting one or more virtual valve deviceconfigurations and retesting the adjusted one or more virtual valvedevice configurations (an exemplary adjustment step 914). Should steps912 or 914 yield satisfactory results (indicative of a suitable virtualvalve for the patient), a physical valve device based upon at least oneof the adjusted virtual valve device configurations may be prepared (anexemplary valve preparation step 916), whereby the prepared valve (suchas an endograft valve device 100 and/or valve system 700 of the presentdisclosure) may be positioned within the patient consistent with anexemplary method 800 of the present disclosure, for example.

Steps 912, 914, and/or 916 may be performed, as referenced above, totest, optimize, and produce a valve (such as a vein valve device) bestsuited for the modeled patient. The virtual testing, as referencedherein, allows for dozens, if not hundreds or thousands or more, ofvirtual devices to be tested, saving significant time and money overtraditional physical valve manufacture and testing. In addition, such amethod, as referenced above, is patient-specific, allowing for anoptimized valve device, specifically tailored for the patient in need ofthe valve procedure (such as a valve replacement or valve insertionwhere no valve is present), resulting in optimal patient treatment. Suchvalve optimization (by way of performing steps 912 and/or 914) may bedone to change one or more parameters, such as valve length, width, wallthickness, leaflet size, leaflet configuration, leaflet number(s),materials, curvatures, and/or a combination of the foregoing, forexample, to optimize a valve for that particular patient. Such anoptimized valve (ultimately produced in step 916, for example), may haveone or more of the desired hemodynamic, mechanical, and/or functionalproperties sufficient for that particular patient's needs. For example,such an optimized valve may have two or more leaflets instead of oneleaflet, and may be optimized so that a minimum amount of energy (or areduced amount of energy) is needed to open and/or close the valve.Other valve configurations may be preferred based upon a differentpatient digital model.

In various embodiments, determination step 908 is based at least in parton the patient venous data and the data indicative of at least onevalve. In other embodiments, determination step 908 is based upon atleast patient venous data indicative of flow and shear stress, andwherein an ultimate determination is based upon a comparison of thepatient venous data indicative of flow and shear stress to at least onethreshold.

Such a tailored approach defines the range of in vivo performance of thevalve in a patient-specific mechanical environment. Although there arefactors beyond mechanics that can be considered, a mechanical approach,and the data emanating therefrom, allows a practitioner to potentiallyidentify non-mechanical factors. For example, if the valve fails in apercentage of the patients that satisfy mechanically-based inclusioncriteria, then additional, non-mechanical biomarkers may be identified(such as blood chemistry, risk factors, co-morbidities, etc.). This datawill then form the basis of a systematic and rigorous approach toembracing this complex patient population.

The third pillar, namely that no valve can function long-term in theabsence of flow (and more specifically shear stress, is addressed asfollows.

Venous Return Assist Device

Transcatheter aortic valve implantation (TAVI) has been successful, inlarge part, because the aortic valve prosthesis is coupled with theheart, namely that the heart pump ensures sufficient flow through theprosthetic. However, this is limited to aortic valves, and does notapply to venous valves, as the heart pump cannot ensure sufficient flowthrough a venous valve.

No valve can function without flow. The disclosure of the presentapplication includes methods to generate venous blood flow (propulsion)through various assist devices (compression) and suction (release)within the vein, such as within the abdominal vena cavae. As discussedin further detail herein, said devices and methods can be used with ourwithout valve implants, as if a native valve is functional, said devicesand methods can be used to facilitate blood flow therethrough.

Under physiologic conditions, the peripheral pump (skeletal muscle), aswell as the respiratory and abdominal phasic pressures, work inconjunction with the compliant veins to assist venous return in thepresence of valves. Unfortunately, in patients of interest, venoushypertension-induced remodeling, thrombosis or fibrosis reduces thecompliance of the veins (thicker and stiffer) and compromises the normalvenous assist mechanisms. In such patients, an active assist mechanismfor venous return is needed.

The present disclosure includes disclosure of an exemplary externalassist device operable to impose a force directly on the externalsurface of the vein to overcome the increased stiffness of the vein. Asshown in FIGS. 10A and 10B, an exemplary assist device 1000 of thepresent disclosure comprises a cuff 1002 configured to fit around ablood vessel and further configured to periodically compress the bloodvessel. Devices 1000, in various embodiments, are operably by way of apower source 1004 operably coupled to cuff 1002, so that power frompower source 1004 can control the compression and relaxation of cuff1002. Power source 1004 may comprise, for example, an implanted battery,which may be rechargeable, and/or a power source 1004 positionedexternal to the patient's body. A processor 1006, operably coupled topower source 1004, is configured to control the rates of compression andrelaxation of cuff 1002. In at least one embodiment, processor 1006 isconfigured so that the compression rate and the relaxation rate can bechanged to a different compression rate and a different relaxation rate.As shown in FIGS. 10A and 10B, an optional connector 1008, such as awire, may be used to connect power source 1004 to cuff 1002, whereinconnector 1008 configured to allow power from power source 1004 to betransmitted therethrough to cuff 1002.

FIG. 10A shows an exemplary assist device 1000 of the present disclosurepositioned around an abdominal vena cava (an exemplary blood vessel1010). Blood flowing from an iliac vein 1012, for example, would flowthrough the vena cava and be assisted using an exemplary assist device1000. Device 1000 is shown in FIG. 10A as positioned around, but notcompressing, the vena cava, while an exemplary device 1000 of thepresent disclosure is shown in FIG. 10B positioned around andcompressing the vena cava. Devices 1000 of the present disclosure arenot limited to being configured around a vena cava, as said devices 1000may be configured to fit around any number of blood vessels within amammalian body.

In at least one embodiment of a device 1000 of the present disclosure,when device 1000 is positioned around a blood vessel at a firstlocation, operation of processor 1006 causes cuff 1002 to alternatelycompress the blood vessel and relax compression of the blood vessel.Processor 1006 controls a compression rate and a relaxation rate (whichmay be the same or different), whereby relaxation at the relaxation ratecauses blood to move through the blood vessel at the first location. Inat least one embodiment, the compression rate is slower than therelaxation rate, as a relatively faster relaxation rate allows the bloodvessel to open quicker and effectively pull blood through the bloodvessel at the first location. A power source 1004 operably coupled tocuff 1002 would be configured to provide power to cuff 1002 and/orprocessor 1006 to facilitate compression and relaxation of cuff 1002.

In various embodiments of devices 1000, processor 1006 is configured sothat the compression rate and the relaxation rate can be changed to adifferent compression rate and a different relaxation rate. In at leastone embodiment, when device 1000 is positioned distal to a blood vesselvalve (such as an endograft valve device 100 as referenced herein),operation of device 1000 causes blood to flow through the vessel valvetoward device 1000. The blood vessel valve may be a native valve or aprosthetic valve, as devices 1000 of the present disclosure areconfigured to facilitate blood flow through both types of valves.

In at least one embodiment, when device 1000 is positioned around theblood vessel at a first location, the blood flows through the bloodvessel at the first location a first rate without operation of device100, and the blood flows through the blood vessel at the first locationat a second rate during operation of device 1000, wherein the secondrate is faster than the first rate. Furthermore, and in variousembodiments, when device 1000 is positioned around the blood vessel at afirst location, the blood flows through the blood vessel at the firstlocation a first rate range without operation of device 100, and theblood flows through the blood vessel at the first location at a secondrate range during operation of device 1000, wherein the second raterange has a faster top rate than the first rate range. The two rangesinclude the slowest relative flow rate, the fastest relative flow rate,and potentially various flow rates in between.

FIG. 11 shows a larger view of an exemplary device 1000 of the presentdisclosure positioned around a blood vessel 1010, and further shows anexemplary endograft valve device 100 positioned within a lumen 1100 of ablood vessel 1012 proximal to where device 1000 is positioned. As shownin FIG. 11, device 1000 is positioned about a vena cava, while device100 is positioned within an iliac vein 1012 proximal to device 1000.Operation of device 1000, when positioned as shown in FIG. 11 relativeto device 100, causes blood to be pulled through vessel 1010 at thelocation of device 1000, and therefore causes blood to be pulled throughdevice 100 proximal to device 1000.

Use of various devices 1000 of the present disclosure provides an assistmechanism where compression of the vein propels the blood flow (in thepresence of functional valve, either native or prosthetic) towards theheart. A quick release of the compression of device 1000 can create theeffect of suction to “pull” the blood from the periphery again in thedirection of the heart. Other devices, such as the devices disclosedwithin US2010/0179376 of Kassab and Navia, may also be configured to fitaround a vessel (such as a vein, as referenced herein) and furtherconfigured to compress and release the blood vessel so to, for example,facilitate blood flow through a vein when the device is positionedaround the vein. Said devices are hereby incorporated into the presentdisclosure by reference.

The present disclosure also includes disclosure of a method offacilitating blood flow through a blood vessel. In at least oneembodiment of a method 1200 of the present disclosure, as shown by themethod steps in FIG. 12, the method comprises the steps of positioningan exemplary external assist device 1000 of the present disclosurearound a blood vessel (an exemplary positioning step 1202), andoperating external assist device 1000 to alternatively compress theblood vessel and relax compression of the blood vessel (an exemplaryoperating step 1204), wherein relaxation of compression causes blood toflow through the blood vessel. Relaxation of compression of device 1000,as referenced herein, causes blood to flow through the blood vessel at afaster rate than a native blood flow rate. In at least one embodiment ofmethod 1200 of the present disclosure, operating step 1204 comprisesoperating external assist device 1000 to alternative compress the bloodvessel at a first rate and to relax compression of the blood vessel at asecond rate, wherein the second rate is faster than the first rate.

Various devices 1000 of the present disclosure may be deliveredminimally invasively through a laparoscopic approach to induce a pumpingaction to propel the flow forward in opposition to gravity.

While various embodiments of devices and methods for assisting valvefunction, replacing venous valves, and predicting valve treatmentsuccesses been described in considerable detail herein, the embodimentsare merely offered as non-limiting examples of the disclosure describedherein. It will therefore be understood that various changes andmodifications may be made, and equivalents may be substituted forelements thereof, without departing from the scope of the presentdisclosure. The present disclosure is not intended to be exhaustive orlimiting with respect to the content thereof.

Further, in describing representative embodiments, the presentdisclosure may have presented a method and/or a process as a particularsequence of steps. However, to the extent that the method or processdoes not rely on the particular order of steps set forth therein, themethod or process should not be limited to the particular sequence ofsteps described, as other sequences of steps may be possible. Therefore,the particular order of the steps disclosed herein should not beconstrued as limitations of the present disclosure. In addition,disclosure directed to a method and/or process should not be limited tothe performance of their steps in the order written. Such sequences maybe varied and still remain within the scope of the present disclosure.

1. An endograft valve device comprising: a first portion having aproximal end, a distal end, an outer portion wall surface and an innerportion wall surface, wherein a tapered wall thickness is definedbetween the inner and outer portion wall surfaces, and wherein the innerportion wall surface further defines a lumen therethrough; and whereinthe first portion has a tapered wall thickness that has a greater wallthickness at the distal end than at the proximal end.
 2. The endograftvalve device of claim 1, further comprising: a second portion comprisinga second portion outer portion wall surface and a second portion innerportion wall surface, wherein a tapered wall thickness is definedbetween the second portion inner wall surface and second portion outerportion wall surfaces; the second portion inner wall surface furtherdefining the lumen therethrough, the lumen extending from a secondportion distal end to a second portion proximal end; wherein the secondportion has a tapered wall thickness that has a greater wall thicknessat the second portion distal end than at the second portion proximalend; and wherein the distal end of the first portion is adjacent to thesecond portion proximal end.
 3. The endograft valve device of claim 1,wherein the first portion comprises a distal end aperture and a proximalend aperture and the distal end aperture has a relatively smallercross-sectional area than the proximal end aperture.
 4. The endograftvalve device of claim 2, wherein a valve is coupled to a portion of theendograft body selected from the group consisting of the first portionat or near the distal end of the first portion and the second portion ator near the second portion proximal end.
 5. The endograft valve deviceof claim 2, wherein the second portion comprises a second portion distalend aperture and a second portion proximal end aperture, where thesecond portion distal end aperture has a relatively smallercross-sectional area than the second portion proximal end aperture. 6.The endograft valve device of claim 2, wherein the first portioncomprises a distal end aperture and a proximal end aperture and thedistal end aperture has a relatively smaller cross-sectional area thanthe proximal end aperture.
 7. The endograft valve device of claim 6,further comprising: the second portion having a second portion proximalend aperture in fluid communication with the distal end aperture of thefirst portion, and the second portion having a second portion distal endaperture wherein the second portion distal end aperture has a relativelysmaller cross-sectional area than the second portion proximal endaperture.
 8. An endograft valve device, comprising: a first portionhaving a proximal end and a distal end; a second portion comprising asecond portion outer portion wall surface and a second portion innerportion wall surface, wherein a tapered wall thickness is definedbetween the second portion inner wall surface and second portion outerportion wall surfaces; the second portion inner wall surface furtherdefining the lumen therethrough, the lumen extending from a secondportion distal end to a second portion proximal end; wherein the secondportion has a tapered wall thickness that has a greater wall thicknessat the second portion distal end than at the second portion proximalend; and wherein the distal end of the first portion is adjacent to thesecond portion proximal end.
 9. The endograft valve device of claim 8,wherein the first portion comprises a distal end aperture and a proximalend aperture; and the distal end aperture has a relatively smallercross-sectional area than the proximal end aperture.
 10. The endograftvalve device of claim 9, wherein the second portion comprises a secondportion distal end aperture and a second portion proximal end aperture;and the second portion distal end aperture has a relatively smallercross-sectional area than the second portion proximal end aperture. 11.The endograft valve device of claim 8, wherein the second portioncomprises a second portion distal end aperture and a second portionproximal end aperture; and the second portion distal end aperture has arelatively smaller cross-sectional area than the second portion proximalend aperture.
 12. The endograft valve device of claim 8, wherein a valveis coupled to a portion of the endograft body selected from the groupconsisting of the first portion at or near the distal end of the firstportion and the second portion at or near the second portion proximalend.
 13. A system comprising an endograft valve device comprising: anendograft body comprising: a first portion having a proximal end, adistal end, a first outer portion wall surface and a first inner portionwall surface, wherein a tapered wall thickness is defined between thefirst inner portion wall surface and first outer portion wall surface,and wherein the first inner portion wall surface further defines a lumentherethrough; wherein the first portion has a tapered wall thicknessthat has a greater wall thickness at the distal end than at the proximalend; a second portion comprising a second portion inner portion wallsurface, further defining the lumen therethrough, the lumen extendingfrom a second portion distal end to a second portion proximal end;wherein the distal end of the first portion is adjacent to the secondportion proximal end; and a valve coupled to a portion of the endograftbody selected from the group consisting of the first portion at or nearthe distal end of the first portion and the second portion at or nearthe second portion proximal end.
 14. The system comprising an endograftvalve device of claim 13 wherein the first portion comprises a distalend aperture and a proximal end aperture and the distal end aperture hasa relatively smaller cross-sectional area than the proximal endaperture.
 15. The system comprising an endograft valve device of claim13 wherein the second portion comprises a second portion distal endaperture and a second portion proximal end aperture; and the secondportion distal end aperture has a relatively smaller cross-sectionalarea than the second portion proximal end aperture.
 16. The systemcomprising an endograft valve device of claim 14 wherein the secondportion comprises a second portion distal end aperture and a secondportion proximal end aperture; and the second portion distal endaperture has a relatively smaller cross-sectional area than the secondportion proximal end aperture.
 17. The system comprising an endograftvalve device of claim 13 wherein the second portion proximal end is influid communication with the distal end of the first portion.
 18. Thesystem comprising an endograft valve device of claim 13 wherein theendograft body is configured for expansion from a collapsedconfiguration to an expanded configuration within a luminal organ. 19.The system of claim 18, wherein the collapsed configuration is sized sothat the endograft body fits within the luminal organ, and wherein theexpanded configuration is sized so that the endograft body is securelypositioned within the luminal organ upon expansion.
 20. The systemcomprising an endograft valve device of claim 13 further comprising: acuff configured to fit around a blood vessel and further configured toperiodically compress the blood vessel; and a processor operably coupledto the cuff, the processor configured to control a compression rate anda relaxation rate; and wherein when the cuff is positioned around theblood vessel at a first location, operation of the processor causes thecuff to compress the blood vessel and relax compression of the bloodvessel, whereby relaxation at the relaxation rate causes blood to movethrough the blood vessel at the first location.